by Racine Nassau, SEAS ’13 and Jessica Neafie, DEES ’12
In the USA, about seven percent of rice is imported while the rest is grown within the country. The average American consumes about nine kilograms of rice per year, and from 2001 to 2009 the USA used on average about 5.5 million tonnes per year (FAO, 2011). Eating rice is a staple for many people all over the world, and it is extremely water intensive in the production stages. Water scarcity is becoming a major problem all over the world and since this could impact food security, countries are examining their ability to grow crops and whether they should choose to import them instead.
Maintenance of water flows through virtual water is one way that countries can control their water problems, and rice, a major staple food that is consumed all over the world, is a major consumer of water.
Virtual water is the water that a country obtains through the goods that they import, so that a country faced with severe water shortages could import their most water intensive goods and instead produce goods that would not tax their water supplies as heavily. The major producers of rice in the world are China, India, Indonesia, Bangladesh, Vietnam, Thailand, Myanmar, Philippines, Brazil, Japan, USA, Pakistan, and the Republic of Korea (in this order).
These countries make up about 3.5 percent of the rice imports into the United States. The amount of influence of these countries on US rice consumption will be examined by looking at US rice trade, the water footprint of the major rice producers, and the environmental impact of one producer over another.
US rice production dominates our consumption at over 90 percent, and the question is whether or not that choice is the best one for our water and our environment.
The US produces rice in Louisiana, California, Texas, Arkansas, and Mississippi throughout regions that could encounter water shortages by 2050 that would impede rice production. Knowing the alternative producers, and examining the environmental and economic efficiency is a requirement for future rice production (particularly if no alternative to reduce the water footprint is achievable).
The water footprint from each country’s rice production changes depending on the climate and irrigation system in that country. The following graph shows the water footprint (m3/t) in the major rice producing countries (Chapagain, 2011):
Vietnam has the smallest water footprint which is roughly half of the U.S. footprint. Japan, South Korea, and China also have smaller water footprints than the U.S., but the U.S. water footprint is still below average when compared to all of the major rice producing countries. Favorable options for rice production could be further examined by looking at the water scarcity in the region and the means of production, then examining whether producing rice in this area is the most economically and environmentally efficient.
One area closely linked to the environmental efficiency of rice is not just the water use but the amount of greenhouse gases produced through production and imports. Although water could potentially be saved by importing rice from countries with smaller water footprints per unit rice produced, when factoring in greenhouse gas emissions this does not necessarily make importing rice the most environmentally friendly choice. Flooded rice fields are a significant source of atmospheric methane, a greenhouse gas which, according to the EPA, is approximately 20 times more effective at trapping heat than carbon dioxide, which has important implications for global warming. The following graph shows the median emission rate of methane for irrigated rice from some of the major rice producing countries (Sass 401).
The U.S. has relatively low methane emission rates for rice production, so importing rice from somewhere like Indonesia or Thailand could not only increase the water footprint, but also increase the greenhouse gas emissions associated with the rice we eat. Transportation of rice to the U.S. results in roughly an additional 2000-2500 kg carbon dioxide per ton rice, if the rice is imported by cargo ship from Asia to New York (Food Miles Calculator).
The following graph shows the methane emissions and water footprint per unit rice side by side for seven of the major rice producing countries.
The only country of the seven compared above that has a better methane and water footprint than the U.S. is South Korea. However, we import very little rice from South Korea (FAO 2011), and the carbon emissions associated with transporting their rice to the U.S. would likely make South Korean rice less environmentally friendly for U.S. consumption than American grown rice.
Due to climate change, pollution, and population increases, the world is seeing its access to fresh water diminish more and more every year. A resource that has been long overlooked because we saw it as renewable, access to freshwater is now a source of concern. Understanding virtual water is an important tool for finding solutions to growing water shortages and scarcity issues. But there is opposition to the idea of using virtual water as a solution: one because staple goods like rice are a much needed commodity and countries are becoming increasingly conscious of their food security; two the prices of goods; and three the carbon footprint produced from the transportation and production of these goods.